400 Ah of batteries in a limited space

I just bought an old ambulance I am converting into an RV. it has a battery compartment for the ambulance module. The compartment is about 19" x 19" square, and about 9 1/2" high. It's wrapped in aluminum, so clearances are important - don't want the battery contacts to hit any of the sides or top, especially when removing/replacing.

I've been trying to figure out how to stuff 400Ah of batteries in there. The high Ah batteries are usually just a tad too high for comfort - really don't want a battery that measures 9 3/8" to the terminals 1/8" away from a nice shiny aluminum plate.

I vaguely remember a flat 400 Ah battery that might fit but I can't find it and I can't remember who makes it.

Any suggestions? Money is of course an issue as well - I can't afford any of the Lithium variants. I'm looking at AGM/Gel batteries.

Comments

  • littleharbor2littleharbor2 Solar Expert Posts: 1,368 ✭✭✭✭
    edited March 30 #2

    The Full River DC400-6 is only 15.9 inches tall. You should be able to fit a pair of these, possibly laying on their sides. The forum's host NAWS sells them.

    Aw shoot! Just caught the 9 1/2 inch height. Any way to modify the height?


    http://www.fullriverbattery.com/product/batteries/DC400-6

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • cptdondocptdondo Solar Expert Posts: 72 ✭✭✭

    Unfortunately no easy way to modify it. The ambulance box is all aluminum and the floor (the top of the battery compartment) is 1" plywood clad in 1/8" aluminum on both sides. it would be a huge undertaking to change it. I have another compartment that could take two of these but it would require a crapload of wiring relocation; there's a 2kW inverter right where the batteries would have to go. Plus I'd have to add the venting. This may be a summer project.....

  • EstragonEstragon Registered Users Posts: 3,840 ✭✭✭✭✭

    These folks make lots of different sizes of AGMs.

    A coat of epoxy over the skin might help, but the thought of batteries and wiring potentially bouncing around in an aluminum box would worry me!

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • littleharbor2littleharbor2 Solar Expert Posts: 1,368 ✭✭✭✭
    edited March 30 #5

    You can squeeze 4 of these in it looks like. You probably want to cap the terminals during installation , connection and removal


    https://www.solar-electric.com/fullriver-dc220-6-agm-sealed-battery-6v-220ah.html

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • cptdondocptdondo Solar Expert Posts: 72 ✭✭✭

    Pretty sure I can make a "donut" with 4 of the Group 27 batteries, yup. Just thought of that. It would be "interesting" to figure out how to secure them and wire them. Maybe prewire them into a single pack and then have a single high power connector....

  • littleharbor2littleharbor2 Solar Expert Posts: 1,368 ✭✭✭✭

    Just what I was thinking. I don't know your access location but I was visualizing sliding them (pre wired) into the battery space off of a temporary platform sitting at the same level.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • m151m151 Registered Users Posts: 20 ✭✭

    I would insulate the top of the compartment, Thin plywood?,contact paper?, wide electrical tape?

  • stmoloudstmoloud Registered Users Posts: 111 ✭✭

    Another option is to use thick rubber straps and 'D' brackets screwed to the floor. Those batteries will never move especially if you contain the lateral movement, easily done by a wooden frame screwed to the floor.

    760W panel array, 4 x 6v 220 ah Crown batteries, Tristar TS-45 PWM controller,  no name 600 PSW inverter. 
  • TecnodaveTecnodave Registered Users Posts: 412 ✭✭✭✭

    Cptdondo,

    If you need a good connector for this the Anderson Power Pole is a 2 circuit connector widely used in industry as a battery connector. Many forklift trucks use these as well as many tow trucks for detachable plug in jumper cables. They are available in several amperage ratings. Use the 300 amp one's for your job. Solar-Electric does stock some Anderson power pole products, maybe they have the 300 amp one's as well

    david

    2 Classic 150, 2 Kid, 5 arrays 7.5 kw total  2ea.  2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200,  2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Exeltech XP-1100,  2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B  dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or LiFePO4,
  • cptdondocptdondo Solar Expert Posts: 72 ✭✭✭

    Thanks everyone.

    I'll have to figure out how to strap the batteries down. The compartment has both a "threshold" and a "header" so once the batteries are in there's room, but I need to figure out how to hold them down so they don't bounce and hit the aluminum top. It's not the best design I've seen.

    I'm thinking a sheet of HDPE over the batteries might do the trick. easy to slide in and out, and pretty rugged. Not sure how it stands up to off-gassing....

    I have a bag of the Anderson connectors in the 150A size. Thanks for the pointer - I got mine from work and unfortunately work shut down rather suddenly so my source is dried up.

  • EstragonEstragon Registered Users Posts: 3,840 ✭✭✭✭✭

    I think many(most/all?) plastics are okay with gassing. If AGMs are gassing though, that's bad news anyway.

    Personally, I'd look for something with some give, so as to avoid squishing the batteries if tight, and to minimize bouncing stress if not. Maybe some sort of high-ish density foam?

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 29,327 admin

    Here is a good size chart of Plastics compatibility (with many chemicals):

    https://www.plasticsintl.com/chemical-resistance-chart

    For forms of rubber/silicone/etc.:

    https://mykin.com/rubber-chemical-resistance-chart

    If you can, highly recommend strapping the batteries down. And insulating the terminals (and rubber grommets where wiring passes through metal walls). Using plastic tubing to help control/route cables can be nice too. Tie cables so they stay in place and don't sag into/onto other things that can damage the insulation.

    Batteries are heavy and rough roads/rough driving/accidents can cause big problems. (my Dad found our old 4x4 truck battery hanging by the battery cables after my sister drove it in the hills one day).

    Also, if you have that much metal around, you might want to look at these fuse blocks that bolt to battery flag terminals very nicely:

    https://www.bluesea.com/products/2151/Dual_MRBF_Terminal_Fuse_Block_-_30_to_300A

    https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

    Fusing right at the battery terminal, or as close as you can, will help reduce the chance of fire.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,331 ✭✭✭✭✭

    Stall Mat from Tractor supply works well as a buffer, if you can get the thickness you need. I use a hunk under the portable generator as a anti vib pad

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • OldManOldMan Registered Users Posts: 128 ✭✭✭

    Do yourself a favor. Unless you plan on winter camping every year, buy lithium. High cost on the front end but you'll enter the 21st century by doing so. When others are complaining about the short life of ANY lead-acid battery, you'll be watching TV and having ice in your margarita.

  • cptdondocptdondo Solar Expert Posts: 72 ✭✭✭

    I've thought about lithium. It's expensive. And as you say, it's temperature tempermental. I do camp in the winter quite a bit. But it's an option. The biggest issue I have is that the BMS is yet another point of failure. This vehicle is supposed to be simple, rugged, and failure tolerant - my heater is a basic propane heater that will work with no electricity.

  • mcgivormcgivor Solar Expert Posts: 2,999 ✭✭✭✭✭

    There are offerings which have an integrated BMS, such as Battleborne which are a drop in replacement type. Sure the initial expense appears to be significantly higher but considering cycle expectancy the difference is not so far apart. Additionally the energy density with Lifepo4 is ~5 times that of lead acid, meaning a smaller footprint or less weight. There is also no need to achieve full charge to maintain battery health, as lithium technology has little to no effect being at a partial state of charge. Yes perhaps the BMS is another failure point, but lead acid have equally or more potential points for failure if not taken care of properly. The advantages of electronics in automotive applications has had a fundemental impact in fuel efficiency, it's much the same in battery technology, there is always the risk of failure, albeit a very minor one, I'm sure the vehicle used dose not have a reliable but inefficient carburetor.

    The change I made to LFP was the best move I've made, the lead acid bank I still have demands way more maintenance, not to say that I neglect the LFP, I do check every day, but lead acid is way more labor intensive, they are flooded by the way, AGM may be better to some degree, but they are still lead acid so still subject to the same fundemental rules.

    The purpose of this post is not to convince one way or the other to the coice made, but merely to enlighten other potentially missed opportunities. My choice was prysmatic cells which require more involvement in ballancing and so forth, but this doesn't dismiss the the potential of a drop in type, which are much simpler for the average user.

    This link https://www.solar-electric.com/battle-born-bb10012-100ah-12v-lithium-battery.html will lead to the description and information, there are much cheaper alternatives in the market but that's up to the purchaser to figure out.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • stmoloudstmoloud Registered Users Posts: 111 ✭✭

    Yes for sure lithium has it's advantages. But IMHO buy a name controller these days, from a company which actually has a reputational stake in the solar industry, and you can almost just set and forget an algorithm which will get your lead acid batteries humming along quite nicely. I would submit to the point where all you have to do is check acid levels once a month and perhaps equalize.

    All quite easy, and quite near to set and forget like the much vaunted and more expensive other chemistries.

    760W panel array, 4 x 6v 220 ah Crown batteries, Tristar TS-45 PWM controller,  no name 600 PSW inverter. 
  • mcgivormcgivor Solar Expert Posts: 2,999 ✭✭✭✭✭

    Not sure I agree with that, LFP with a well designed BMS monitors each cell or cell group shutting down charging or discharge should one differ from the others beyond a given threshold , prevents overcharging, over discharge, temperature protection, short circuit protection, over discharge current protection and cell ballancing.

    Lead acid is primitive in its basic form, even with the best controllers cells can fail, often going undetected until it's too late to reverse damage, more so with monoblock batteries where it's more difficult to remediate problematic cells. Flooded do have the distinct advantage of measuring SG, unlike AGM, but both are still the same fundemental construction. LA also requires a long absorption period to near or achieve full charge which is a distinct disadvantage in solar applications, the usable voltage range is wider, they do not tolerate partial states of charge, or discharge below 50% well.

    Currently I still have a flooded LA bank in service, it has been for the most part trouble free but requires constant maintenance, mostly watering and cleaning terminals due the corrosive nature of the electrolyte. When they do finally expire, I'm prepared to spend the extra 70-80% to replace them with LFP based on experience with both.

    Yes LFP dose have some limitations or challenges , especially in colder ciimates where temperatures below freezing are possible, but being in a tropical location myself that is not an issue, in fact it was the primary reason for the switch, as LA do not tolerate high temperature well, LA life expectancy in temperatures of ~35°C are cut in half, the LA batteries themselves are often in the 40°C+ in my particular case. The LFP on the other hand are usually below ambient day temperature due to the overnight cooling, on mast days often 10°C cooler.

    In the end we all make our choices and pay our money, personal choice is a an individual decision based on the information available or experience gained, however experience is, in my opinion, worth more than second hand information, in other words don't take my word, try experiencing the unknown there may be a few supprises. Remember the first cell phones with a LA battery? It was commonly referee to as a brick, there would be no slim smart phones if LA technology was still used.....enough said.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • EstragonEstragon Registered Users Posts: 3,840 ✭✭✭✭✭

    I'm not entirely sure about lithium in heat, as I recall reading about materially faster capacity loss for EV batteries in warm/hot climates. Although EV is obviously a much different application, and generally different lithium chemistries than off-grid, this may still apply to some extent.

    It will be interesting to hear how your bank does in the years to come.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • OldManOldMan Registered Users Posts: 128 ✭✭✭

    Given your winter camping (better you than me), yeah, stick with lead-acid. My idea of winter is a margarita on the beach at Puerto Penascso. Tacos for supper. LOBSTER tacos.

  • mcgivormcgivor Solar Expert Posts: 2,999 ✭✭✭✭✭

    Heat increases capacity at the expense of life expectancy with all chemistries, it's a matter of what temperature the degredation begins. The optimal for lifepo4 is 30°C, LA is 25°C, the problem is, LA generate more internal heat as they charge, in hot climates where the overnight temperatures are high, the latent heat has no way if dissapating due to the sheer mass of lead, so the next day they get a little hotter. My observations are that the LFP being more efficient tend not to have the temperature add on effect and are always ~4°C below ambient during the day.

    Automotive applications are very different due to the high charge and discharge currents needed, this can cause them to generate heat. The maximum charging current for my bank is 400A or 1C, the maximum I use is ~0.1C 40A so not driven hard, similarly the discharge is very light on average, yes I purposely oversized to reduce generator needs and extend the cycle expectancy, it may appear the PV is a little on the low side, but as SOC is not an issue it recovers over a few days after a cloudy period.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • EstragonEstragon Registered Users Posts: 3,840 ✭✭✭✭✭

    Yeah, EV batteries must have a much tougher life than off-grid. Regenerative braking and lots of stop/start high rate charging/discharging must take a toll. Sitting a few inches above hot tarmac can't help either.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mike_smike_s Registered Users Posts: 79 ✭✭

    When you talk of "life," you seem to be referring to storage capacity, not expected time to replacement. Good FLAs can go 8-10 years. 2-3 seems expected for cell phone / laptop lithiums. Are large ones that much better, and have they even been out long enough to know in the real world?

  • mcgivormcgivor Solar Expert Posts: 2,999 ✭✭✭✭✭
    edited April 10 #25

    The life expectancy, number of cycles, is largely dependent on how batteries of any chemistry are treated. The amount of capacity withdrawn will determine the life expectancy to a large degree, there are other factors such as temperature which play a part, this makes it difficult to generalize. To establish a baseline testing is done under ideal conditions, so while a manufacturer may claim a figure of X number of cycles, real world results will vary considerably. To make matters more confusing there are different standards used by different manufacturers, making an apple to apple comparison difficult.

    The testing usually uses grid power which allows for extended periods of charging, whereas solar charging has a limited window of opportunity, this means the charging current may be significantly higher than the recommended slow charging, which will have a negative impact on expected results.

    Using the cell phone example, many people change when the battery is at or near to completely discharged, if charged when depleted to 20% , the life will be significantly improved and rather than 2-3 years, it may last double that. The same applies to other uses, as a general rule lead acid life expectancy drops significantly if discharged below 50%. Lithium on the other hand allow discharge to 20% of their capacity without significant impact on cycle life expectancy. Since lithium has a larger usable range, the usable capacity is therefore greater. Should the depth of discharge be much less the cycle count could be dramatically improved with both, however lead acid has a finite life span so if not used and kept in float, they will eventually die of old age. Lithium are purported to have a much longer shell life so to speak, however either way if you're not using them you're loosing them.

    This is a very complex subject without definitive answers, taking the time to study will answer many questions and create some new ones at the same time.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • OldManOldMan Registered Users Posts: 128 ✭✭✭
  • mike95490mike95490 Solar Expert Posts: 8,331 ✭✭✭✭✭

    For a mobile application, LFP Lithium batteries are much smaller and lighter, and have less mounting restrictions than lead acid batteries, which all have to allow for eventual failure and gassing .

    But LFP cells quickly start loosing capacity below 40F and cannot be easily recharged below 32F (freeze point)

    LFP does require a battery Management system (BMS) to prevent damage to them

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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